duke@435: /*
duke@435:  * Copyright 1999-2007 Sun Microsystems, Inc.  All Rights Reserved.
duke@435:  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
duke@435:  *
duke@435:  * This code is free software; you can redistribute it and/or modify it
duke@435:  * under the terms of the GNU General Public License version 2 only, as
duke@435:  * published by the Free Software Foundation.
duke@435:  *
duke@435:  * This code is distributed in the hope that it will be useful, but WITHOUT
duke@435:  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
duke@435:  * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
duke@435:  * version 2 for more details (a copy is included in the LICENSE file that
duke@435:  * accompanied this code).
duke@435:  *
duke@435:  * You should have received a copy of the GNU General Public License version
duke@435:  * 2 along with this work; if not, write to the Free Software Foundation,
duke@435:  * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
duke@435:  *
duke@435:  * Please contact Sun Microsystems, Inc., 4150 Network Circle, Santa Clara,
duke@435:  * CA 95054 USA or visit www.sun.com if you need additional information or
duke@435:  * have any questions.
duke@435:  *
duke@435:  */
duke@435: 
duke@435: #include "incls/_precompiled.incl"
duke@435: #include "incls/_ciObject.cpp.incl"
duke@435: 
duke@435: // ciObject
duke@435: //
duke@435: // This class represents an oop in the HotSpot virtual machine.
duke@435: // Its subclasses are structured in a hierarchy which mirrors
duke@435: // an aggregate of the VM's oop and klass hierarchies (see
duke@435: // oopHierarchy.hpp).  Each instance of ciObject holds a handle
duke@435: // to a corresponding oop on the VM side and provides routines
duke@435: // for accessing the information in its oop.  By using the ciObject
duke@435: // hierarchy for accessing oops in the VM, the compiler ensures
duke@435: // that it is safe with respect to garbage collection; that is,
duke@435: // GC and compilation can proceed independently without
duke@435: // interference.
duke@435: //
duke@435: // Within the VM, the oop and klass hierarchies are separate.
duke@435: // The compiler interface does not preserve this separation --
duke@435: // the distinction between `klassOop' and `Klass' are not
duke@435: // reflected in the interface and instead the Klass hierarchy
duke@435: // is directly modeled as the subclasses of ciKlass.
duke@435: 
duke@435: // ------------------------------------------------------------------
duke@435: // ciObject::ciObject
duke@435: ciObject::ciObject(oop o) {
duke@435:   ASSERT_IN_VM;
duke@435:   if (ciObjectFactory::is_initialized()) {
duke@435:     _handle = JNIHandles::make_local(o);
duke@435:   } else {
duke@435:     _handle = JNIHandles::make_global(o);
duke@435:   }
duke@435:   _klass = NULL;
duke@435:   _ident = 0;
jrose@1424:   init_flags_from(o);
duke@435: }
duke@435: 
duke@435: // ------------------------------------------------------------------
duke@435: // ciObject::ciObject
duke@435: //
duke@435: ciObject::ciObject(Handle h) {
duke@435:   ASSERT_IN_VM;
duke@435:   if (ciObjectFactory::is_initialized()) {
duke@435:     _handle = JNIHandles::make_local(h());
duke@435:   } else {
duke@435:     _handle = JNIHandles::make_global(h);
duke@435:   }
duke@435:   _klass = NULL;
duke@435:   _ident = 0;
jrose@1424:   init_flags_from(h());
duke@435: }
duke@435: 
duke@435: // ------------------------------------------------------------------
duke@435: // ciObject::ciObject
duke@435: //
duke@435: // Unloaded klass/method variant.  `klass' is the klass of the unloaded
duke@435: // klass/method, if that makes sense.
duke@435: ciObject::ciObject(ciKlass* klass) {
duke@435:   ASSERT_IN_VM;
duke@435:   assert(klass != NULL, "must supply klass");
duke@435:   _handle = NULL;
duke@435:   _klass = klass;
duke@435:   _ident = 0;
duke@435: }
duke@435: 
duke@435: // ------------------------------------------------------------------
duke@435: // ciObject::ciObject
duke@435: //
duke@435: // NULL variant.  Used only by ciNullObject.
duke@435: ciObject::ciObject() {
duke@435:   ASSERT_IN_VM;
duke@435:   _handle = NULL;
duke@435:   _klass = NULL;
duke@435:   _ident = 0;
duke@435: }
duke@435: 
duke@435: // ------------------------------------------------------------------
duke@435: // ciObject::klass
duke@435: //
duke@435: // Get the ciKlass of this ciObject.
duke@435: ciKlass* ciObject::klass() {
duke@435:   if (_klass == NULL) {
duke@435:     if (_handle == NULL) {
duke@435:       // When both _klass and _handle are NULL, we are dealing
duke@435:       // with the distinguished instance of ciNullObject.
duke@435:       // No one should ask it for its klass.
duke@435:       assert(is_null_object(), "must be null object");
duke@435:       ShouldNotReachHere();
duke@435:       return NULL;
duke@435:     }
duke@435: 
duke@435:     GUARDED_VM_ENTRY(
duke@435:       oop o = get_oop();
duke@435:       _klass = CURRENT_ENV->get_object(o->klass())->as_klass();
duke@435:     );
duke@435:   }
duke@435:   return _klass;
duke@435: }
duke@435: 
duke@435: // ------------------------------------------------------------------
duke@435: // ciObject::set_ident
duke@435: //
duke@435: // Set the unique identity number of a ciObject.
duke@435: void ciObject::set_ident(uint id) {
duke@435:   assert((_ident >> FLAG_BITS) == 0, "must only initialize once");
duke@435:   assert( id < ((uint)1 << (BitsPerInt-FLAG_BITS)), "id too big");
duke@435:   _ident = _ident + (id << FLAG_BITS);
duke@435: }
duke@435: 
duke@435: // ------------------------------------------------------------------
duke@435: // ciObject::ident
duke@435: //
duke@435: // Report the unique identity number of a ciObject.
duke@435: uint ciObject::ident() {
duke@435:   uint id = _ident >> FLAG_BITS;
duke@435:   assert(id != 0, "must be initialized");
duke@435:   return id;
duke@435: }
duke@435: 
duke@435: // ------------------------------------------------------------------
duke@435: // ciObject::equals
duke@435: //
duke@435: // Are two ciObjects equal?
duke@435: bool ciObject::equals(ciObject* obj) {
duke@435:   return (this == obj);
duke@435: }
duke@435: 
duke@435: // ------------------------------------------------------------------
duke@435: // ciObject::hash
duke@435: //
duke@435: // A hash value for the convenience of compilers.
duke@435: //
duke@435: // Implementation note: we use the address of the ciObject as the
duke@435: // basis for the hash.  Use the _ident field, which is well-behaved.
duke@435: int ciObject::hash() {
duke@435:   return ident() * 31;
duke@435: }
duke@435: 
duke@435: // ------------------------------------------------------------------
jrose@1424: // ciObject::constant_encoding
duke@435: //
duke@435: // The address which the compiler should embed into the
duke@435: // generated code to represent this oop.  This address
duke@435: // is not the true address of the oop -- it will get patched
duke@435: // during nmethod creation.
duke@435: //
duke@435: //
duke@435: //
duke@435: // Implementation note: we use the handle as the encoding.  The
duke@435: // nmethod constructor resolves the handle and patches in the oop.
duke@435: //
duke@435: // This method should be changed to return an generified address
duke@435: // to discourage use of the JNI handle.
jrose@1424: jobject ciObject::constant_encoding() {
duke@435:   assert(is_null_object() || handle() != NULL, "cannot embed null pointer");
jrose@1424:   assert(can_be_constant(), "oop must be NULL or perm");
duke@435:   return handle();
duke@435: }
duke@435: 
duke@435: // ------------------------------------------------------------------
jrose@1424: // ciObject::can_be_constant
jrose@1424: bool ciObject::can_be_constant() {
jrose@1424:   if (ScavengeRootsInCode >= 1)  return true;  // now everybody can encode as a constant
jrose@1424:   return handle() == NULL || !is_scavengable();
jrose@1424: }
jrose@1424: 
jrose@1424: // ------------------------------------------------------------------
jrose@1424: // ciObject::should_be_constant()
jrose@1424: bool ciObject::should_be_constant() {
jrose@1424:   if (ScavengeRootsInCode >= 2)  return true;  // force everybody to be a constant
jrose@1424:   return handle() == NULL || !is_scavengable();
duke@435: }
duke@435: 
duke@435: 
duke@435: // ------------------------------------------------------------------
duke@435: // ciObject::print
duke@435: //
duke@435: // Print debugging output about this ciObject.
duke@435: //
duke@435: // Implementation note: dispatch to the virtual print_impl behavior
duke@435: // for this ciObject.
duke@435: void ciObject::print(outputStream* st) {
duke@435:   st->print("<%s", type_string());
duke@435:   GUARDED_VM_ENTRY(print_impl(st);)
jrose@1424:   st->print(" ident=%d %s%s address=0x%x>", ident(),
duke@435:         is_perm() ? "PERM" : "",
jrose@1424:         is_scavengable() ? "SCAVENGABLE" : "",
duke@435:         (address)this);
duke@435: }
duke@435: 
duke@435: // ------------------------------------------------------------------
duke@435: // ciObject::print_oop
duke@435: //
duke@435: // Print debugging output about the oop this ciObject represents.
duke@435: void ciObject::print_oop(outputStream* st) {
duke@435:   if (is_null_object()) {
duke@435:     st->print_cr("NULL");
duke@435:   } else if (!is_loaded()) {
duke@435:     st->print_cr("UNLOADED");
duke@435:   } else {
duke@435:     GUARDED_VM_ENTRY(get_oop()->print_on(st);)
duke@435:   }
duke@435: }